Restoration of Labral Anatomy and Biomechanics After Superior Labral Anterior-Posterior Repair

Abstract

Background: Both simple and mattress repair techniques have been utilized with success for type II superior labral anterior-posterior (SLAP) lesions; however, direct anatomic and biomechanical comparisons of these techniques have yet to be clearly demonstrated. Hypothesis: For type II SLAP lesions, the mattress suture repair technique will result in greater labral height and better position on the glenoid face and exhibit stronger biomechanical characteristics, when cyclically loaded and loaded to failure through the biceps, compared with the simple suture repair technique. Study Design: Controlled laboratory study. Methods: Six matched pairs of cadaveric shoulders were dissected, and a clock face was created on the glenoid from 9 o’clock (posterior) to 3 o’clock (anterior). For the intact specimen, labral height and labral distance from the glenoid edge were measured using a MicroScribe. A SLAP lesion was then created from 10 o’clock to 2 o’clock. Lesions were repaired with two 3.0-mm BioSuture-Tak anchors placed at 11 o’clock and 1 o’clock. For each pair, a mattress repair was used for one shoulder, and a simple repair was used for the contralateral shoulder. After repair, labral height and labral distance from the glenoid edge were again measured. The specimens were then cyclically loaded and loaded to failure through the biceps using an Instron machine. A paired t test was used for statistical analysis. Results: After mattress repair, a significant increase in labral height occurred compared with intact from 2.5 ± 0.3 mm to 4.3 ± 0.3 mm at 11 o’clock (P = .013), 2.7 ± 0.5 mm to 4.2 ± 0.7 mm at 12:30 o’clock (P = .007), 3.1 ± 0.5 mm to 4.2 ± 0.7 mm at 1 o’clock (P = .006), and 2.8 ± 0.7 mm to 3.7 ± 0.8 mm at 1:30 o’clock (P = .037). There was no significant difference in labral height between the intact condition and after simple repair at any clock face position. Labral height was significantly increased in the mattress repairs compared with simple repairs at 11 o’clock (mean difference, 2.0 mm; P = .008) and 12:30 o’clock (mean difference, 1.3 mm; P = .044). Labral distance from the glenoid edge was not significantly different between techniques. No difference was observed between the mattress and simple repair techniques for all biomechanical parameters, except the simple technique had a higher load and energy absorbed at 2-mm displacement. Conclusion: The mattress technique created a greater labral height while maintaining similar biomechanical characteristics compared with the simple repair, with the exception of load and energy absorbed at 2-mm displacement, which was increased for the simple technique. Clinical Relevance: Mattress repair for type II SLAP lesions creates a higher labral bumper compared with simple repairs, while both techniques resulted in similar biomechanical characteristics.